Projection apparatus.



No. 803,385. PATENTED OCT. 31, 1905.

P. H. WYNNE.

PROJECTION APPARATUS.

APPLICATION FILED JULY 28.1905.

2 SHEETS-SHEET 1.

- PATENTED OCT. 31, 1905. P. H. WYNNE.

PROJECTION APPARATUS.

APPLICATION FILED JULY 28.1905.

2 SHEETS-SHEET 2.

. UNITED STATES PATENT OFFICE.

PHILIP HENRY WYNNE, OF BOSTON, MASSAOH USETTS, ASSIGNOR, BY DI- RECT ANDMESNE ASSIGNMENTS,

OF ONE-HALF TO AGNES WYNNE AND ONE-HALF TO L. E. KNOTT APPARATUSCOMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

PROJECTION APPARATUS.

Specification of Letters Patent.

Patented Oct. 31, 1905.

Application filed July as, 1905. Serial No. 271,534.

To all whom it may concern.-

Be it known that I, PHILIP HENRY WYNNE, a citizen of the United States,residing at Boston, county of Suffolk, and State of Massachusetts, haveinvented an Improvement in Projection Apparatus, of which the followingdescription, in connection with the accompanying drawings, is aspecification, like numerals on the drawings representing like parts.

This invention relates to that class of projection apparatus which isdesigned to project an image either from a transparent object, such as alantern-slide, or from an opaque ob- 5 ject. These two ways ofprojecting I will refer to for convenience as transparent projection andopaque projection. In most projection apparatus of this class with whichI am familiar the opaque object to be projectedis sustained in avertical plane. While this method of supporting the object is feasibleso long as the object is in the nature of a plate or a card, yet it isnot practical if the opaque object is of such a character that it cannotbe turned out of a horizontal position without destroying ordisarranging the View which it is desired to project. For instance, thesaid method of supporting the object would not be feasible if the viewit was desired to project on the screen were one showing the arrangementwhich iron filings on a sheet of paper will take when a horseshoe-magnetis placed beneath the paper or is any other physical experiment whichcan only be observed 5 in plan view, because the very act of turning thepiece of paper or other apparatus showing the physical experiment intothe vertical position would clisarrange and destroy the experiment whichwas to be projected. I have improved this type of apparatus by providinga construction in which the opaque object to be projected may besustained in'a horizontal position, so that it is possible to projectalmost any object whether it be one which could be readily put into avertical position, as a card, or one which could not be so placed, asthe physical experiment above referred to, or an open vessel containingliquid, &c.

In most projection apparatus the projected image of the opaque object isnecessarily a perverted imagethat is, an image similar to the image seenin a mirror-unless the projected image is rectified by use of anadditional mirror or some equivalent device.

My improved projection apparatus is so constructed that the projectedimage is an erect one, both inversion and perversion of the image beingavoided.

In order to accomplish these objects, I provide means for sustaining theopaque object in a horizontal position and interpose in the path of thebeam oflight emanating from the source of illumination a mirror sodisposed as to reflect said beam onto the opaque object, thereby toillumine said object and then use the same mirror to reflect through theobjective those light-rays emanating from the illuminated object whichare to be projected on the screen. Said mirror therefore stands in thepath of and reflects successively the rays emanating from the source ofillumination and those emanating from the illumined object. Since therays emanating from the illumined object are reflected by the mirrorbefore they pass through the objective, the

image which is projected through the objective is a reflected image ofthe illumined object, and therefore the perversion caused by thereflection in the mirror corrects that caused by the projection on thescreen and the image appears on the screen in its correct position. Saidmirror therefore performs two functions. First, it reflects theilluminatingrays onto the object and performs the function of anilluminating-mirror, and, secondly, it reflects the rays radiated fromthe object and by so doing prevents the perversion of the projectedfigure, and thereby becomes an image-erecting mirror. I shall thereforehereinafter refer to this mirror as a combined illuminating and erectingmirror.

In order to convert my apparatus from an opaque-projection apparatus toa transparentprojection apparatus, I use a second mirror to cooperatewith the illuminating and erecting mirror, said second mirror being sodisposed as to receive the reflected illuminatingrays from thefirst-named mirror and then reflect said rays back to said mirror, saidreflected rays being again reflected by the firstnamed mirror in thedirection of the objective. In using the apparatus as thus arranged thetransparency to be projected will be placed in the path of thethrice-reflected beam of light,

IOO

or, in other words, between the combined illuminating and erectingmirror and the objective.

In the drawings which illustrate an apparatus embodying my invention,Figure 1 is a horizontal section through said apparatus when arrangedfor opaque projection. Fig. 2 is a vertical section on the line .1100,Fig. 1. Fig. 3 is a view similar to Fig 1, showing the apparatus whenarranged for transparent projection. Fig. 4 is a section on line y 3Fig. 3. Fig. 5 is a perspective view of two mirrors arranged to show theprinciple on which my apparatus works. Fig. 6 is a plan view of theframe supporting the mirror 20, and Fig. 7 is a side elevation of Fig.6.

The source of illumination, the condensinglens, and the objective-lensmay be of any suitable or usual construction, and in order to simplifythe drawings 1 have shown these elements conventionally.

3 designates a source of illumination which is herein illustrated as anarc-light, and 4 designates the usual condensing-lenses which areusually used in this class of apparatus. The objective is designated by5. These elements are supported in any suitable or usual way upon theoptical bed 6, which is shown as supported by stands 7, rising from abed or table 8.

The center line 10 of the condensing-lenses and the center line 11 ofthe objective are nonparallel and may have any convenient angularrelation to each other. As herein shown, said center lines are arrangedto form between them an angle of substantially thirty degrees, althoughit will be obvious that my invention is not limited to this angle.

Situated in the path of the beam of rays 12, collimated by thecondensing-lenses 4:, is a mirror 13, which, when the apparatus is usedfor opaque projection, is a combined illuminating and erecting mirror,as will be presently described. This mirror stands at an inclination ofabout forty-five degrees to the plane in which the center lines 10 and11 lie. In this embodiment of my invention said plane is a horizontalplane. With the mirror so placed the beam 12 from the condensing-lens isreflected thereby downwardly, and if an object is placed in a horizontalposition beneath said mirror to receive said reflected beam such objectwill obviously be illuminated by said beam. ith my apparatus an opaqueobject is thus illuminated by reflected rays originally emanating fromthe source of illumination. The opaque object thus illuminated willobviously radiate light-rays in all directions, and those which strikethe mirror 13 in a vertical direction will be reflected in a horizontalline through the objective and thus projected onto the screen. Theobject which is thus projected is therefore, in fact, the reflection ofthe object in the mirror 13. In order that the reflected image of theilluminated object which is thus projected on the screen may be readilyfocused, I prefer to arrange the mirror 13 square onto the center line11 of the objectivelens, as shown in the drawings, and to so incline themirror that the rays which emanate vertically from the illuminatedobject are the ones which are reflected through the objective. Thisparticular arrangement of mirror 13 is not essential, however, althoughI deem it preferable. The only essential feature is that said mirrorshall be so placed as to reflect the collimated rays from thecondenser-lens onto the object to be illuminated and then reflect somerays from the object toward the objective.

The mirror 13 may be supported in any usual or suitable way. I haveherein shown it as detachably secured to and forming the back side of acasing 16, which is adapted to rest on the optical bed 6, said casinghaving the proper shape, so that when the mirror is slipped into theways 17 it stands in the required inclined position. The bottom of thecasing 16 is provided with an opening 18 beneath the mirror 13, and theopaque object 74 to be projected may be placed directly on the table 8or on any suitable support beneath said opening, so as to receive thereflected illuminating-rays. Said casing is also provided with ways 19,in which opaque objects, such as cards, may be slid, or in which anysuitable holder supporting an opaque object may be supported.

It will be understood, of course, that all parts of the apparatus arecovered by suitable hoods 75.

In order to change my apparatus over into one adapted for transparentprojection, I place another mirror 20 beneath the mirror 13 and inposition to receive the rays reflected thereby, said mirror 20 being sodisposed as to reflect back onto the mirror 13 the reflection of thesource of illumination, and I then place the transparent object in aholder 21, interposed between the objective 5 and the mirror 13. Withthis arrangement of the parts the rays 12 from the condensing-lensesstrike the mirror 13 and are reflected thereby down onto the mirrorQO,and by this mirror 20 are again reflected onto the mirror 13, and bythis mirror 13 still again reflected forward through the transparency inthe holder 21 and the objective 5. The illuminatingrays are reflectedthree times, twice by the mirror 13 and once by the mirror 20; but sincethese mirrors can be made to reflect substantially all of the rays verylittle loss of light occurs. By this arrangement of mirrors it ispossible to use the same objective for transparent projection as is usedfor opaque projection, and the change from one to the other does notinvolve a resetting of the instrumentorachange of position of thescreen, but simply the placing of a mirror 20 to receive the raysreflected from the mirror 13.

Where the mirror 13 is arranged square with the objective-lens, it isnecessary to give the mirror 20 the proper inclination, as shown in thedrawings, so that it will reflect the rays back onto the mirror 13.

It will be noted from Figs. 1 and 3 that the rays 12 strike the mirror13 at an angle, and therefore while each ray is reflected downwardly ina vertical plane owing to the fortyfive degree inclination of themirror13 said rays are also reflected at an inclination in said verticalplane, as seen in Fig. 5. If the mirror 20 were placed horizontally,each reflected ray 14 would be reflected back again in the same verticalplane, but at an opposite inclination, and would again be reflected bythe mirror 13 to one side of theobjective; but by properly inclining themirror 20 the rays 14 are reflected back to the mirror 13 at such anangle that upon being reflected a second time by the mirror 13 they canpass through the objective.

Any suitable holder 21 for the transparent object may be employed, andin order not to confuse the drawings I have illustrated said holderconventionally only.

It will thus be seen that my apparatus comprises in its construction amirror arranged to reflect the rays emanating from the source ofillumination onto an object (whether said object be the opaque objectwhich it is desired to project onto the screen or simply a reflector,such as a mirror 20, to reflect back to the mirror 13 the rays whichsaid reflector receives therefrom) and also to reflect toward theobjective the rays emanating from the illumined object. When the deviceis used as an opaqueprojection apparatus, the object is' the opaqueobject which it is desired to project, and when the apparatus is usedfor transparent projection the object is a reflector which is adapted toreflect back to the mirror 13 the rays which it receives therefrom. Bythe term object therefore, as used to define the article on which therays from the source of illumination are reflected, I mean either theopaque object to be projected or a reflector.

It will be obvious, of course, that any suitable reflector may be usedfor the combined illuminating and erecting mirror, and by the termmirror I intend to cover any suitable reflector, whether it be silveredglass, polished metal, or of any other suitable construction.

From the above it will be seen that my apparatus is an extremely simpleone, but that it accomplishes results not possible with any of theprojection apparatus in which the opaque objects to be projected must besustained in a vertical plane.

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a projection apparatus, a source of illumination, anobjective-lens, and a combined illuminating and erecting mirror toreflect light from the source of illumination toward an object, and toreflect toward the objective the light which is emanated or reflectedfrom the object. f

2. In a projection apparatus, asource of illumination,a condensing-lens,an objective-lens, and a combined illuminating and erecting mirrorarranged at an angle of about forty-five degrees to the plane containingthe median lines of the condensing-lens and the objectivelens.

3. In a projection apparatus, a source of illumination,anobjective-lens, a condensing-lens, means to support an object in a planeparallel to the plane containing the median lines of the condensing-lensand the objective-lens, and a combined illuminating and erecting mirrorto reflect light from the source of illumination onto said object andalso to reflect light emanating or reflected from the illumined objectto the objective.

4. In a projection apparatus, a source of illumination, means tocollimate light-rays emanatingtherefrom and direct them horizontally, anobjective-lens, and a reflector to receive the collimated light-rays andreflect them onto an object, said reflector being so disposed as toreflect toward the objective the light emanated or reflected from theobject.

5. In a projection apparatus,a source of illumination, acondensing-lens, an objective-lens, a combined illuminating and erectingmirror arranged at an angle of about forty-five degrees to a horizontalplane, and means to support it in position to receive the reflected raysfrom said illuminating and erecting mirror, said latter mirror alsobeing so positioned as to reflect toward the objective the rays whichemanate or are reflected from said object.

6. In a projection apparatus,a source of illumination, anobjective-lens, a casing having an open end which is directed'towardboth the source of illumination and the objective, a combinedilluminating and erecting mirror within the casing, and means to supportan object to receive the light reflected from said mirror, said mirrorbeing also disposed so as to receive and reflect toward the objectivelight emanated or reflected from the object.

7. In a projection apparatus,a source of illumination, anobjective-lens, a casing having an open end directed toward said sourceof illumination and objective-lens, a mirror within the casing, saidcasing having an opening beneath the mirror, and means to support anobject beneath said opening, said mirror being so arranged as to reflectonto the object the rays emanating from the illumined object.

8. In a projection apparatus, two optical beds, a source ofillumination, and a condensing-lens mounted on one optical bed, anobjective-lens mounted on the other optical bed, a casing carried byboth beds, said casing having an open end directed toward the source ofillumination and the objective-lens and also an opening in its bottom, amirror above said In testimony whereof I have signed my name opening andarranged at forty-five degrees to to this specification in the presenceof two sub- IO a horizontal plane and so disposed as to reflect scribingwitnesses. throug 1 the opening the rays emanating from r 5 the sourceof illumination, thereby to illumi- PHILIP HENRY YNNE' nate an objectplaced beneath the opening, and Witnesses: also to reflect toward theobjective rays ema- LOUIS G. SMITH, nating from the illumined object.BERTHA F. HEUSER.

